Electrical calculating equipment for telephone systems



Aug. 26, 1941. wRlGHT 2,253,596

ELECTRICAL CALCULATING EQUIPMENT FOR TELEPHONE SYSTEMS Filed Feb. 16,1939 6 Sheets-Sheet 1 IIllIlll l 7M5 Con/7201 lNl EN TOR E. R G. WR/GH TGP. M

A 7' TORNEV Aug. 26, 1941. wRlGHT 2,253,596

ELECTRICAL CALCULATING EQUIPMENT FOR TELEPHONE SYSTEMS Filed Feb. 16,1939 6 Sheets-Sheet 2 ll'lllllll llllll l 000000000 OOOOOOOO\ INVENTORE. R G. WRIGHT aam A TTORNEV Aug. 26,1941. WRIGHT 2,253,596

ELECTRICAL CALCULATING EQUIPMENT FOR TELEPHONE SYSTEMS Filed Feb. 16,1959 6 Sheets-Sheet 3 lNl ENT E. R 6. WR/GH T ATTORNEY 26, 1941- E. P.G. WRIGHT 2,253,596

ELECTRICAL CALCULATING EQUIPMENT FOR TELEPHONE SYSTEMS Filed Feb. 16,1959 I 6 Sheets-Sheet 4 lNl ENTOR E. R G. WR/GH 7' 1941- E. P. G. WRIGHT2,253,596

ELECTRICAL CALCULATING EQUIPMENT FOR TELEPHONE SYSTEMS Filed Feb. 16,1939 6 Sheets-Sheet 5 FIGS ATTORNEY I Aug. 26, 1941. E. P. c. WRIGHT2,253,596

ELECTRICAL CALCULATING EQUIPMENT FOR TELEPHONE SYSTEMS Filed Feb. 16,1939 6 Sh'fD-s-Sheet 6 6 A 5 TLl f nl-blalnhn m OOOO OOOOOOOOOOOOO O O OO O O 0 O O I ONE PULSE ONE PULSE PER ONE PULSE PER MINUTE TEN MINUTESPER HOUR f 70 PEI/WFE INVENTOR E. P G. WRIGHT ATTORNEY i Patented Aug.26, 1941 ELECTRICAL CALCULATING EQUIPMENT FOR TELEPHONE SYSTEMS EsmondP. G. Wright, London, England, assignor to Western Electric Company,Incorporated, New York, N. Y., a corporationof New York ApplicationFebruary 16, 1939, Serial No. 256,651 In Great Britain April 1, 1938 13Claims.

This invention-relates to telephone systems and more particularly toelectrical calculating equipment for use in conjunction with automaticticketing facilities associated with telephone lines.

The object of the invention is to provide common calculating equipmentcapable of performing several calculations simultaneously and/or oftransmitting the results of different calculations simultaneously to anumber of associated circuits.

One feature of the invention comprises electrical calculating equipmentcomprising a number of register circuits adapted to register differentvariable digital values (e, g., times, numbers, etc.) and an associatedcalculating circuit arranged to register a digital value (e. g., time,number, etc.) and adapted to perform simultaneously similar calculations(e. g., subtraction) between the digital value recorded in thecalculating circuit and each digital value registered in a plurality ofregister circuits.

Another feature of the invention comprises electric calculatingequipment including a digit transmitting circuit adapted to transmit, inturn, code impulses the different combinations of which arecharacteristic of every possible value of a digit, a number of digitreceiving circuits, and connecting devices for selectively connectingdifferent selections of the digit receiving circuits to the digittransmitting circuit while each code impulse is being transmitted,whereby the receiving circuits can receive simultaneously diflerent codeimpulse combinations characteristic of different values of a digit.

The invention will be described in relation to automatic telephonesystems in which information regarding'long distance calls is to beautomatically recorded for tariff purposes on thesocalled automaticticketing basis. In such systems, it is proposed to store the callingand called parties numbers and the duration of a telephone connectionduring conversation to print a ticket after conversation ceases. It isalso desired, in such circumstances, to print the duration of the callfor each connection, and the embodiment of the invention to be describedbelow includes a calculating circuit which comprises switches thatrecord the time of day to within a minute and are arranged to beconnected to any one or more conversation circuits, conversation overwhich ceases at about the same time to perform simultaneouslysubtractions of the conversation duration times recorded in thesewaiting conversation circuits from the actual time of day, and totransmit the different originating times simultaneously to the differentconversation circuits for printing on the corresponding tickets.

I The invention will be clearly understood from the followingdescription of the embodiment shown in the accompanying drawings inwhich:

Fig. 1 shows a switch and an associated circuit that controls thetransmission and printing of the various digits relating to theoriginating time;

Figs, 1 to 4, inclusive, show six minute switches AF. These switches inconjunction with each other will determine the conversation time for aperiod not exceeding fifty minutes. The connections to and themultiplying of the six switches are indicated in Figs. 1 and 2;

Fig. 5 shows two ten-minute switches TI and T2 and an hour switch H; and

Fig. 6 shows the sequence switch S for controlling the operation of thecircuit.

To completely disclose the invention, Figs. 1, 3

and 5 should be placed side by side in the order named with Figs. 2, 4and 6 placed beneathFigs. l, 3 and 5, respectively.

A master clock (not shown) steps switches AF each minute, switches Tl,T2 each ten minutes and switch H once an hour through the operation ofrelays MR, TMR, and HR. When switches AF, TI and T2 are all in theirnormal positions, the time is between an exact hour and one minute pastthe hour. Switch H is in normal position between minutes 59 and 1.Groups of six contacts of switches Tl, T2 are multipled,

' and groups of twelve contacts in the upper four banks of switch H aremultipled.

The associated conversational circuits (not shown) comprise -pointduration-recording switches arranged to be stepped for each minute ofconversation, as, for instance, the switch represented by thedesignation DUR, the arm of which is stepped a terminal per minute byclockdriven means (not shown) as soon as the called subscriber removesthe receiver from the switchhook. Marking leads extend from markingbanks of said switches to a marking multiple the wires of which areconnected to the banks of the six 10-wiper 10-point minute switches AF.Multiple wires 0 9 are connected to the contacts 0-9 in bank level amll,and the contacts in bank levels am0am9 are multipled in the staggeredmanner shown in Fig. l. The switches AF take care of less thanten-minute intervals and the multiple from contact 0 of level am!) isconnected to ten different positions in the ten different levels ofswitch A. Contacts l-9 in bank level bmll are also connected to themultiple wires l9 and these contacts are multipled to conbmll.

each multiple wire I9 has a connection to ten 1 different positions inten different bank levels of switches A and B, the zero multiple wirebeing multipled in switch A only. The multiple wires I III9 aresimilarly connected to multipled groups of contacts in switches B, 0,wires II-I 9 being connected to contacts I9 of bank level cm! as well asto contacts III-I9 of bank level Similarly multiple wires 20-29 areconnected to switches C, D; 3039 to switches D, E; 40-49 to switches E,F. Only that portion of the bank of F corresponding to the unusedportion of the bank of A is used.

The wipers of switch A are connected to front contacts of a group ofrelays AI, A2, A4, A8; the wipers of switch B to the front contacts ofrelays BI; B2, B4, B8, and the wipers of switch Fto front contacts ofrelays FI, F2, F4, F8.

The groups of relays AIA8, FI-F8 are each connected to multipledcontacts of the banks of the ten-minute switches TI and T2 in such amanner that they are allocated to the six different ten-minute intervalsin an hour,

the A relays being allocated to the intervals II9,

. and the F relays to the interval 50-59.

The maximum call duration which we are con.- sidering is fifty minutesand, therefore, if the time at the end of a connection is between -50minutes past the hour, e. g., 10.24, the call may have started before orafter oclock. If the time at the end of conversation is between 0-10minutes past the hour then a call of almost any duration within thefifty-minute interval may have started before the hour and so on. Fordifferent purposes which will appear later, the switches TI and T2 arearranged to operate the relay groups AI-AB, etc., in differentpositions;

The digits to be printed are sent to the printer via the conversationcircuit by a four-unit code over wires LI--L4, Fig. 6, under control ofcode relays WI-W4. It will be seen that for digit 1, WI alone isoperated, and earth is connected to LI only. For digit 5 (4+1), W4 andWI are operated, and earth is connected to LI and L3. For a spacing,signal, relays W4, W8 are operated and earth is connected to L3, L4.

The time switches are stepped by means of minute, ten-minute, and hourrelays MR, TMR, HR, respectively, which receive a short pulse at the endof each corresponding time period. If a pulse is received by one or moreof these relays while the circuit is in'use, the relay or relaysTen-minute switch TI is arranged to operate over its wipers groups ofrelays corresponding to the ten-minute intervals orfraction thereofincluded in the actual time; thus in position 1 the A relays only can beoperated, in position 2 the A and B relays can be operated, while inposition 6 all the relay groups can be operated.

Ten-minute switch T2 is arranged to operate the relay groupscorresponding to ten-minute intervals greater than that which includesthe minute portion of the actual time; thus in position 1 (actual timebetween 0-10 minutes past the hour) the B-F relay groups can beoperated, while in position 6, no relay groups are operated.

If the hour, of the actual time is 1 or 10, the

preceding hour differstherefrom in number of digits. Wipers Tim-3, hm4of hour switch H take care of variations in the first digit. This switchis standing in the first position 1 between the hours of 1 and 2. Bankhm4 is arranged to give the first digit for the hour preceding theactual time, so that contacts I, II and I2 are connected to code wire CIfor initiating registration of digit 1 for the first digit, 'whilecontacts 2 |o are connected to code wide C48 for initiating theregistration of a space after the first digit.

Bank hm3 gives the first digit of the actual hour, so that contacts I&are connected to C48 and III, II and I2 to CI.

Banks hmI, hm2 take care of the seconddigit of the hour, bank hml forthe actual hour,'bank -hm2 for the preceding hour. The wires CI--C6 frombanks hml,'hm2 are connected to wires CI-Cll in the circuits of coderelays WI-W4, Fig. 6.

The circuit has to be able to give a correct indication simultaneouslyto different connections lock to off-normal bank sm5 of the sequenceswitch S and, therefore, the time switches cannot be stepped untilsequence switch S again reaches normal.

Thus the time recorded when the circuit is seized is maintained in thecircuit until it has 'been recorded by the printer associated with theconversation circuits.

Leads TLI, TLZ, TL3, Fig. 6, are connected to three armatures of relay Tin Fig. 5. When an indication is required from one or more conversationcircuits, the wire STL is grounded, the relay ST operates and a circuitis provided, battery through the left winding of relay IG throughcontacts 4 of relay MR, contacts 4 of relay TMR, contacts 3 of relay HR,contacts I of relay ST and the home position of wiper sm5 to ground. Theleft winding of IG is short-circuited by the springs MP8 of aninterrupter machine while these springs are closed. When the springsopen, IG operates and locks through its right winding and No. Icontacts, No. 4 contacts in parallel with the No. 2 contacts of relay STover the previously traced circuit to ground on sm5 in its normalposition.

The No. 3 contacts of relay IG open the shortcircuiting path across theleft winding of IG and complete the circuit for the magnet SM which isimpulsed by the interrupter contacts ZILPS to step switch S. Thiscircuit extends from ground at the normal contact of sm5 over the No. Icontacts of ST, the No. 3 contacts of HR, the No. 4 contacts of TMR, theNo. 4 contacts of MR, interrupter contacts 20.PS, No. 3 contacts of 1Gto battery through the winding of SM. when the switch advances toposition 2, wiper sml extends ground via the No. 2 contacts of IG, leadTLI, No. I back contact of relay T, Fig. 5, through the No. 4 backcontact of relay N, No. 3 back contact of P, No, 2 back contact of M,No. 5 back contact of N and No. 4 back contact of P to the wiperstmZI-tmZS, respectively. At the same time wiper sm2 extends ground viathe No. 2 contacts of IG, lead TL3, No. 3 back contacts of relay T, Fig.5, to wiper hm4. In

this position 2 of sequence switch S, a spacing code is offered to theconversation circuits if the hour is 2-10, and digit 1 if the hour is 1,11 or 12. Ground connected to Wiper hm4 is thus connected to conductorcI or 048 and operates relay WI or relays W4 and W8. This is for thefirst digit of the preceding hour; that is, the hour in whichconversation commenced over the conversation circuit.

For these preceding hour codes to be required by a conversation circuit,the duration of call recorded therein must be greater than the number ofminutes past the hour recorded on switches, Tl, T2, AF. It will berecalled that ground is connected in parallel to wipers tm2ltm25. Assumethat the time is 10:24 and that switch T2 will be standing on its No. 3contacts. Relay groups Dl-D8, E|--E8, FI-F8 will, therefore, becomeenergized and connect earth to all wipers of switches D, E, F. Theswitches AF are standing on their No. 5 contacts and, therefore,

ground via switch D will be connected to leads 25-34, via switch E toleads 35-44 and via switch F to leads 45-49. I

If,- therefore, the duration switch of any conversation circuit waitingvfor an indication is recording more than twenty-four minutes ofconversation, relay OT will be operated via the duration switch DUR toconnect up code responsive relays or printer magnets to leads Ll-L4.

The digit l or the space code will, therefore, be recorded ready forprinting.

If the duration recorder of a waiting conversation circuit is recordingtwenty-four minutes or less, its relay OT will .not be operated and thecode connected to Ll--L4 will not be received thereby.

The ofiering of the above code takes place in position 2 of sequenceswitch S. When S moves to position 3, relay groups D, E, F and theoperated code relays are released, and relay T is energized in a circuitover wiper'sm4 to ground at the No. 2 contact of relay IG and switchesto the actual hour recorded instead of the preceding hour.

Switch A grounds leads 4, switch B grounds leads.5l4 and switch-Cgrounds leads l524 to the duration-recording switches of the associatedconversation circuits. The code receiving equipment ofwaitingconversation circuits in which durations of twenty-four minutes or lessis recorded will be connected up by their respective relays 0T operatedfrom ground via the corresponding one of leads 0-24.

When switch S steps to position 5, relay T, relay groups A, B, C and theoperated code relays release. Ground is now connected via No. 2 contactof relay IG, wiper sm4 and lead PL to the waiting conversation circuitsto cause the recorded digit or space to be printed.

Thus if the conversation duration is more than twenty-four minutes andthe actual time is less than twenty-four minutes past any hour, theconversation must have started in the preceding hour and consequently ifthe actual time is either 1, 11 or 12 oclock a first digit 1 for thepreceding hour 12, or 11 will be printed, but if the actual time iseither 2, 3, 4, 5, 6, 7, 8, 9 or 10 oclock a space will .be printed asthe preceding hour will be 1, 2, 3, 4, 5,6, 7, 8 or 9 o'clock and nofirst digit will be required. If the conversation duration is less thantwenty-four minutes past any hour and the actual time is twentyfour ormore minutes past the same hour, the conversation must have started inthe current hour and consequently if the actual time is either 10, 11 or12 oclock a first digit 1 will be printed, but if the actual time is atl, 2, 3, 4, 5, 6, 7, 8, or 9 o'clock a space will be printed as no firstdigit will be required.

When switch S steps to position 6, ground is connected to leads TLI, TL2instead of to leads TLI, TL3. Relay T is not operated so that, asbefore, relaysgroups D, E, F are operated via TLI. ,Ground via TL2, No.2 back contact of relay T and wiper hm2 operates a combinationof coderelays Wl-W4 for the second or only digit of the preceding hour and thiscode is registered by waiting conversation circuits in which a callduration of more than twenty-four minutes is recorded.

In position 7 switch S operates relay T and releases relay groups D, E,F and the operated code "or less is recorded. In position 9, a printingsignal is sent via PL to the waiting circuits to cause the second oronly digit to be printed.

11 or 12 oclock, a second digit 2, 1, 2, 3, 4, 5, 6, '7,

8, 9, 0 or 1 respectively will be printed but, if the conversationdurationis less than twenty-four -minutes past any hour and the actualtime is twenty-four or more minutes p st the same hour, then for theactual hours 1, 2, 3, 4, 5, 6, '7, 8, 9, 10, 11 or 12, a second digit 1,2, 3 4 5, 6, 7, 8, 9, 0, 1 or 2, respectively, will be printed.

In this way the actual hour or the preceding hour registered by switch Hhas been recorded in automatic ticketingprinters associated with waitingconversation circuits according to the individual duration records insaid conversation circuits.

Sequence switch S now steps to position 10 in which relay T is notoperated and all the relay groups A--F are operated by ground applied toall wipers of the switches Tl, T2 and over conductors TLI and TL4 coderelays W4 and W8 are operated by ground applied over wiper SM4 toconductor C48. The connecting relays of all waiting conversationcircuits are operated and a space code is registered by said circuits.

In position 11, all relay groups and code relays are released and anoperate signal is sent via PL to cause theprinters to space and torelease the connecting relays. Relay M is operated in this position toprepare for recording of the tens minute digits of the originatingtimes.

Switch TI is used to control the tens digit if the conversationoriginating time was in the same hour as the conversation time. Wipertmlll con-" natlng conversation time was in the hour preceding theconversation terminating time. As the maximum conversation durationwhich can be recorded is fifty minutes, 00-99 minutes in the precedinghour is impossible and, therefore, the five levels of T2 are sufficient,tm2l-tm25 controlling tens digit values l-'-5 respectively.

In determining the tens and units minute digit values, a subtraction hasto be automatically made of the conversation duration from the record ofconversation termination time. This is performed in four stages, and thecomplete code for a digit value may be sent in one, two or three stages.In positions 12, 14, 16, 18, respectively,

of switch S, code relays WI, W2, W4, W8 are in- I dividually operated.These relays send individual signals over corresponding wires LIL4, theindividual signals signaling a digit value 1, 2, 4, 8, respectively. Ifthe tens digit to be sent is 3, 5, 6, 7, 9, or 0, signals must be sentover two or more Wires; for 3, signals over Ll, L2 in positions 12 and14; for signals over Ll, L3 in positions 12 and 16; for 6, signals overL2, L3 in positions 14 and 16; for 7, signals over L1, L2, L3 inpositions 12, 14 and 16; for 9, signals over LI, L4 in positions 12 and18; for 0, signals over L2, L4 in positions 14 and 18. The above code intabular form is as follows: I

Code

Digit :cooqomewrowo It will be seen that for every odd digit value, asignal must be sent in position 12; the operation of relay M, therefore,connects ground to the odd numbered wipers of both switches Tl, T2. Ifthe originating time of a call was fifty minutes or more past the hourin which the call has terminated, the call duration must have been lessthan ten minutes; therefore, in bank tml5 of switch T I only the No. 6contact is connected up and this only operates the A group of relays forchecking whether the call duration was less than ten minutes. If theoriginating time was between ten and nineteen minutes past the same hourthat the call terminates, the terminating time may be between eleven,say, and fifty-nine and the duration must have been less than tenminutes if TI v is on contact 2 so that the A group of relays isoperated, and so on, the duration being less than energized in position11 of switch S the relay .groups B via wiper tml I, D via wiper tm25,and

F via wiper tm23, are energized.

Switches B, D, F are on contacts 5 and, therefore, earth will beconnected to leads 5-; --3l, and 45-49.

If as assumed the actual time is twenty-four minutes after 10 o'clockand a duration switch has advanced to connect with any lead between 5and 14 indicating a conversation duration of five to fourteen minutes,the actual starting time for the conversation must lie between 24-14 and245 minutes after 10 o'clock or between 10:10 and 10:19, or if theswitch has advanced to connect with any lead between 25 and 34,indicating a conversation duration of twenty-five to thirtyfour minutes,the actual starting time for the conversation must lie between 24-34 or-10 and 2425 or -1 minutes before 10 o'clock or in fact between 9:50 and9:59; or if the switch is advanced to connect with any lead between 45and 49 indicating the conversation duration of forty-five to forty-nineminutes, the actual starting time for the conversation must li between24-49or --25 and 2445 or ---21 minutes before 10 o'clock or in factbetween 9:35 and 9:39.

If the duration switches of any waiting conversation circuit arestanding on the correspond- "ing contacts they will receive ground viaswitch B, D or F and their duration switches to operate their respectivconnecting relays which connect up their code register magnets toreceive the pulse on LI to record the digit 1 as the total code of thetens digit for those duration switches which are connected to leads 5H;as part of the code of the digit 5 for those duration switches which areconnected to leads 25-34; and as part of the code of the digit 3 forthose duration switches which are connected to leads When sequenceswitch S steps to position 13, relay M and relay groups B, D, F arereleased as well as the connecting relays of the waiting conversationcircuits.

Relay N is operated in position 13, remains operated when switch S stepsto position 14 and connects ground to tml0, tml2, tml3, tm22 and t1n23,and relay W2 is operated to offer a ground pulse on lead L2 (digit value2), required for originating tens minute digit values, 0, 2, 3 forforty-nine if TI is on contact 6, that is, indicating a terminating timeof fifty minutes or more past the hour.

Similarly with T2. If the originating time of a call was less'thantwenty minutes past the preceding hour in which the call terminates, theterminating time cannot be greater than nine minutes past the followinghour and, therefore, only the first (and multipled) position of tm2l isconnected up and that is connected to the F group of relays as theduration must have been forty-one minutes or more. If the originatingtime of a call was between 3039 minutes past the preceding hour, thenthe terminating time cannot be more than twenty-nine minutes past thehour and, in consequence, only the first three contacts of tm23 areconnected up and these energize respectively the D, E, F groups of relayaccording as the terminating time is 0-9; 10-19; and 20-29 minutes pastthe hour.

Let us take the previous assumption of a terminating time of 10:24. Thewipers of switches Tl, T2 are on contacts 3 and when relay M is past 10oclock, and 2, 3 for past 9 o'clock. With switches TI and T2 in position2 the C, A, F relay groups are operated. With switches A, C, F inposition 5, leads 0-4; I524; 45-49 are grounded. These duration timesgive corresponding originating times 10:2010:24; 10:00- 10:09;9:35-9:39, for which alone signal L2 is required as the total code ofthe.digit for the times 10:20l0:24, as part of the code for the digitOfor the times 10:0010:09 and as part of the code of the digit 3 for thetimes 9:35- 9:39. Those conversation switches of which the durationswitches are standing on any one of contacts 0-4; l5-24; -49, therefore,receive the 2 code over wire L2.

When sequence switch S moves to position 15, relays N and W2 and the A,C, F relays release. Relay P operates and remains operated when switch Ssteps to position 16 in which position relay W4 is operated to offer the4 code signal over L3 to the waiting conversation circuits.

Relay P grounds wipers tmll, tml5, tm24 and tm25 corresponding tooriginating times of 4049 minutes past the hour and the preceding hour,50-59 minutes past the hour and the preceding hour.

With switches TI and T2 in position 3, relay groups D and E are operatedso that switches D, E are rendered efiective. No relay groups areoperated via switch TI because an originating time between 10.40 and10.59 is, of course, impossible. Ground via wipers of switches D and Eis connected to leads 25--34 and 35-44. Durations of 25-44 minutes givean originating time of 40-59 minutes past nine and, therefore, a signalover lead L3 as the complete code of the tens digit 4 for the times9:40-9:49 and as part of the code of the tens digit 5 for the time 9:50-

Once again, connecting relays of waiting conversation circuits may beoperated; this time if their duration switches record durations of 25-44minutes. Such circuits will record the 4 signal over wire L3.

When switch S steps to position 17, relays P and W4, and relay groups D,E release, relay Q is operated and remains operated when switch S stepsto 18, in which position relay W8 is operated. The 8 code is onlyrequired for digit (the other part of the code for this digit being L2)and, therefore, relay Q only grounds wiper tmlfl to operate relay groupCIC8 so that leads I -24 only are grounded. Duration times of 15-24 meanan originating time range 10:00- 10:09, and the 8 code signal via L4 issent to the waiting conversation circuits which require it. The coderegisters of waiting conversation circuits may, therefore, have any oneof th following relay or magnet combinations energized: 1, 2, 1 and 2,4, 1 and 4, and 2 and 8.

When switch S steps to position 19, relays Q and W8 and relay groupCI-C8 release, and a an odd numbered terminal indicating a durationtimehaving an odd. number of minutes. If, howprinting signal is sent viaPL to cause the reg- .istered' digits to be printed and the registersreleased.

In addition, in position 19, relays AI, BI,FI are operated over theirleft windings. Taking BI as an example, it grounds wipers bml, bm3, bm5,bmI and bm9 of switch B and, taking position 5 for the units digit ofthe terminating time, if any duration switch is standing on its terminalconnected to lead 13, indicating a duration time of thirteen minutes,the actual starting time must be then 10:24-13 or 10:11 thus closing acircuit from ground over bank level bmI for preparing the conversationcircuit to register the code digit 1 as a part of the units digitregistration ,3; if any duration switch is standing on its terminalconnected to lead 11, indicating a duration time of eleven minutes, theactual starting time must be then 10:24-11 or 10:13 thus closing acircuit from ground over bank level 170113 for preparing theconversation circuit to register a code digit 1 as a part of the unitsdigit registration 3; if any duration switch is standing on its terminalconnected to lead 9, indicating a duration time of nine minutes, theactual starting time must have been 10:24--9 or 10:15, thus closing acircuit from ground over bank level M5 for preparing the conversationcircuit to register a code digit 1 as a part of the units digitregistration 5; if any duration switch is standing on its terminalconnected to lead 7, indicating a duration time of seven minutes, theactual starting time must have been 10:247 or 10:17, thus closing acircuit from ground over bank lever bmI for preparing the conversationcircuit to register a code digit 1 as a part of the units digitregistration ever, the actual or terminating time has an odd number ofminutes, ground will be connected by the operation of these relays toeven numbered terminals of the duration switches and when therefore anyduration switch is set upon an even numbered terminal a circuit will beprepared to a register for registering the code digit 1. As an exampleassume that the terminating time is 10:25 and that a duration switch isset upon a terminal connected to lead I4, indicating a duration time offourteen minutes, then the starting time must have been 10:2514 or 10:11and the operation of relay BI will there- 'fore establish a circuit fromground over the position 6 terminal of the bank bmI, lead I4 and thenceto the conversation circuit for preparing the register thereof toregister the code digit 1.

When switch S steps to position 20, relay WI is operated and the 1 codesignal is received by waiting conversation circuits, the durationswitches of which are registering an odd minutes duration.

Switch S then steps to 2| in which the AI-FI relays and relay WI arereleased and the A2F2 relays are energized to ground the 0, 2, 3, 6 and'7 wipers of the switches AF. Contacts of relay B2 ground level bml) tosubtract duration units equal to the terminating time units recorded onB thus giving an originating time minutes unit 0.

Contacts of relay B2 ground level bm2 to subtract units digits two lessthan those recorded, thus giving an originating time minutes unit 2.

Contacts of relay B2 ground bm3, bmG, bm'l to subtract respectively:units digits 3 less than those recorded; units digits 6 less; and unitsdigits 7 less than those recorded.

Considering the operation of relay B2, if the terminating time is forexample 10:20 and switch B is therefore in position 1 and any durationswitch is standing on its terminal 10, indicating a duration time of tenminutes, the starting time must have been 10:20-40 or 10:10, or if theterminating time is for example 10:21 and switch B is therefore inposition 2 and any duration switch is standing on its terminal 11,indicating a duration time of eleven minutes, the starting time musthave been 10:21-11 or 10:10. In either case a circuit is closed fromground over bank level bmll for preparing the associated conversationcircuit to register a code digit "2 as a part of the units digitregistration 0. If the terminating time is for example 10:22 and switching time is for example 10:23 and switch B is in position 4 and anyduration switch is standing on its terminal 11, indicating a durationtime of eleven minutes, the starting time must have been 10:23-11 or10:12. In either case a circuit is closed from ground over bank level M2for preparing the associated conversation circuit to register a codedigit 2. If the terminating time is, for example, 10:24 and switch B isin position 5 and any duration switch is standing on its terminal 11,indicating a duration time of eleven minutes, the starting time -musthave been example :26 and switch B is in position 7, and' any durationswitch is standing on its terminal 10, indicating a duration time of tenminutes, the starting time must have been 10:26-10 or 10:16 or if theterminating time is for example 10:27 and switch B is in position 8 andany duration switch is standing on its terminal 11, indicating aduration time of eleven minutes, the starting time must have been10:27-11 or 10:16. In either case the circuit is closed from ground overbank level bmfi for preparing the associated conversation circuit toregister the code digit 2 as a part of the units digit registration 6.If the terminating time is for example 10:28 and switch B is in position9 and any duration switch is standing on its terminal 11, indicating aduration time of eleven minutes, the starting time must have been10:28-11 or 10:17 or if the terstanding on its terminal 12, indicating aduration time of .twelve minutes, the starting time must have been10:29-12 or 10:17. In either case a circuit is 1 closed from ground overbank level Inn] for preparing the associated conversation circuit toregister a code digit 2 as a part of the starting time must have been10:21-7 or 10:14. In either case a circuit is closed from ground overbank level bm4 for preparing the associated conversation circuit toregister a code digit "4. If the terminating time is for example 10:22and switch B is in position "3 and any duration switchis standing on itsterminal 7, indicating a duration time of seven minutes, the startingtime must have been 10:22-7 or 10:15 or if the terminating time is forexample 10:23 and switch B is in position 4". and any duration switch isstanding on its terminal 8, indicating a duration time of eight minutes,the

starting time must have been 10:23-8 or 10:15.

In either case a circuit is closed from ground over bank level bmli forpreparing the associated conversation circuit. to register a code digit"4 as a part of theunits digit registration 5. If the terminating timeis for example 10:24 and switch B is in position 5" and any durationswitch is standing on its terminal 8, indicating a duration time ofeight minutes, the starting time must have been 10:24-8 or 10: 16 or ifthe terminating time was for example 10:27 and switch B is in position 8and any duration switch is standing on its terminal 11, indicating aduration time of eleven minutes, the starting time must have been10:27-11 or 10:16. In either case a circuit is closed from ground overbank level bm6 Ior the units digit registration 7. Other similar cir- Ithe associated conversation circuits to register the code digit 2.

Relays A2, C2, D2, E2 and. F2 function in a similar manner. erated inwaiting conversation circuits, the originating conversation times forwhich have a units minutes digit 0, 2, 3, 6, or 7 for preparing suchcircuits to receive the 2 code signal. When thereafter switch S advancesinto position 22, code relay W2 is operated and relays A2 to F2 remainoperated. With relay W2 operated, conductor L2 is grounded and the codesignal 2 is thereby registered in all prepared conversation circuits.

In position 23 of switch S relays A4 to F4 are operated to connectground to the 4, 5, 6 and 7 wipers of switches A to F and relays A2 toF2 and relay W2 are released. Taking relay B4 as an example, if theterminating time is 10:20'

and switch B is therefore in position 1 and any duration switch isstanding on its terminal 6, indicating a duration time of six minutes,the starting time must have been 10:20-6 or 10:14, or if the terminatingtime is for example 10:21 and switch B is therefore in position "2 andany duration switch is standing on its terminal 7, indicating a durationtime of seven minutes,

Thus connecting relays are op-' preparing the associated conversationcircuit to register a code digit 4 as a part of the units digitregistration 6. If the terminating time is for example 10:25 and switchB is in position 6 and any duration switch is standing on its terminal8, indicating a duration time of eight minutes, the starting time musthave been 10:25-8 or 10:17 or if the terminating time is for example10:28- and switch B is in position 9 and any duration switch is standingon its terminal 11, indicating a duration time of eleven minutes, thestarting time must have been 10:28-11 or 10:17. In either case thecircuit is closed from ground over bank level bml for preparing. theassociated conversation circuit to register a code digit 4 as a part ofthe units digit registration 7. Other similar circuits are prepared inthe several positions of switch B over its grounded wipers and in theseveral positions of switches A, C, D, E and F over their groundedwipers for preparing associated conversatlon circuits to register thecode digit "4.

Thus connecting relays are operated in waiting conversation circuits,the originating times of which have a' units digit 4, 5, 6 or 7 forpreparing such circuit to receive the 4 code signal. When thereafterswitch S advances into position 24,

code relay W4 is operated and relays A4 to F4 remain operated. Withrelay W4 operated conductor L4 is grounded and the code signal "4 isthereby registered in all prepared conversation circuits.

In position 25 of switch S, relays A4 to F4 and code relay W4 arereleased and relays A8 to Fl are operated to connect ground to the O, 8and 9 wipers of switches A to F. Taking relay B8 as an example, it theterminating time is 10:20 and switch B is in position 1 and any durationswitch is standing in position 10, indicating a duration time of tenminutes, then the starting time must have been 10:20-10 or 10:10 or ifthe terminating time was 10:25 and switch B is in position 2, and anyduration switch is standing on terminal 11, indicating a duration timeoi eleven minutes, then the starting time must have been 10:21-11 or10:10. In either case a circuit is closed from ground over wiper b'mOfor preparing the associated conversation circuit to register a codedigit 8 as apart of the digit registration 0. If the terminating time is10:22 and switch B is in' position 3 and any duration switch is standingin position 14, indicating a duration time of fourteen minutes, then thestarting time must have been :22-14 or 10:08 or if the terminating timeis 10:23 and switch B is in position 4 and any duration switch isstanding in position 10 15, indicating a duration time of fifteenminutes, then the starting time must have been 10:23-15 or 10:08. eithercase a circuit is closed from ground .over wiper M8 for preparing theassociated conversation circuit to register a code digit "8. If theterminating timeis 10:24 and switch B is in position 5 and any dura ionswitch is standing in position 15, indicating a duration time of fifteenminutes, then the starting time must have been 10:24-15 or 10:09 or ifthe terminating time is 10:25 and switch B is in position 6 and anyduration switch is standing in position 16, indicating a duration timeof sixteen minutes, then the starting time must have been 10:25-16 or10:09. In either case a circuit is closed from ground over wiper M9 forpreparing the associated conversation circuit to register a code digit8" as a part of the units digit registration 9. Other similar circuitsare prepared in the several positions of switch B over its groundedwipers and in the several positions of switches A, C, D, E and F overtheir grounded wipers for preparing associated conversation circuits toregister the code digit "8.

Thus connecting relays are operated in waiting conversation circuits,the originating times for which have a units digit 0, 8 or 9 forpreparing such circuits to receive the 8" code digit signal. Whenthereafter switch S advances into position 26, code relay W8 is operatedand relays A8 to F8 remain operated. With relay W8 operated, conductorL8 is grounded and the code signal 8'is thereby registered in allprepared conversation circuits.

To recapitulate in all conversation circuits which were prepared asabove outlined to register the units digit 1 only, the code signal 1will be registered; in circuits prepared to register the units digit 3,code signals "1 and "2 will be registered; in circuits prepared toregister the units digit 5, code signalsv 1-and "4 will be registered;in circuits prepared to register the units digit 7, code signals 1, 2and "4 will be registered;. in circuits prepared to register the unitsdigit 9, code signals 1" and "8 will be registered; in circuits preparedto register the units digit-2, code signal 2 .will be registered; incircuits prepared to register the units digit 6, code signals "2 and 4will be registered and in circuits prepared to register the units digit0, code signals 2 and "8 will be registered. In position 27, a printingsignal will be sent via PL to all waiting conversation circuits to printthe digit corresponding to the registered code signal or signals and torelease the register magnets. The conversation circuits then releaserelay ST. Switch S homes and releases IG. If one or more relays HR, TMR,MR have been operated and locked they are now released 70 and thecorresponding switches are stepped.

It is usual to charge diiferent rates for calls initiated at differenttimes of day on toll and trunk calls. For instance, there may be onerate from nine in the morning till 2 P. M., a cheaper 7 afternoon ratefrom 2 P. M. till '7 P. M., and a special night rate from 7 P. M. till 9A. M.

Wipers hm5, hmfi of the hour switch H are arranged to signal the tariffrate by full ground, resistance ground, and absence of ground on asignal lead KL, Figs. 5 and 6, to the conversation circuits. Inpositions 2 and 4 of sequence switch S ground is connected via No. 2contact of relay IG, wiper sm2, lead JL, to banks hm5, hm6. If theoriginating time was in the preceding hour and the tariff needs apositive signal, ground via JL is connected direct or through resistanceRS, via hm6, No. 4 back contact of relay T, lead I KL, Figs. 3 and 6,front contacts of the conversation circuit connecting relayto tariffrate relays when switch S is in position 2.

If the originating time was in the same hour as the terminating time,the connecting relays of the conversation circuit is not operated when Tis normal but only when T is operated, and

ground or resistance ground, if required, is connected to the tariffrate relays when switch S is in position 4 via wiper hm5.

The contacts of .wipers hmli, hmt are differently wired to give thecorrect tariff rate for the same hour and preceding hour respectively.

Alternatively, a single wiper could be used merely to signal that, owingtothe originating time being in the preceding hour, the tariff rate tobe charged is different from that applying at the moment. Theinformation given in this case may merely indicate a preceding tariffrate,- or the actual tariff rate to be charged. This information may beused in any desired manner.

What is claimed is:

1. In a telephone system, settable means for denoting the elapsed timeof a telephone conversation, settable means for denoting the hour andminutes digits of the terminating time of the conversation, means forcalculating from said settings the starting time of the conversation andmeans controlled by said calculating means for producing code signalsindicative of the digits of the hour and minute of said starting time.

2. In a telephone system, settable means for denoting the elapsedminutes of duration of a telephone conversation, settable means fordenoting the hour and minutes digits of the terminating time'of theconversation, means for subtracting the elapsed minutes setting from theterminating time setting for determining the hour and minute of thestarting time of the conversation and means for producing code impulsesindicative of the hour and minute of said starting time.

3. In a telephone system, settable means for denoting the ele. edminutes of duration of a telephone/convers tion, settable means fordenoting the hour and minutes digits of the terminating time of theconversation, means for determining from the elapsed minutes setting ifsaid conversation started in the same hour or in the hour preceding theterminating time, means for subtracting the elapsed minutes setting fromthe terminating minutes setting for determining the minutes digit of thestarting time and means for transmitting code pulses ingliicative of'the hour and minute of said starting 4. ma telephone system, a,plurality of settable means for denoting the elapsed times of aplurality of simultaneously occurring telephone conversations and acalculating equipment common thereto comprising settable means fordenoting the hour and minutes digits of the terminating time of saidconversations, means for simultaneously calculating from said elapsedtime setting and from said terminating time setting the starting timesof all of said conversations and means for transmitting code impulsesindicative of the digits of the hour and minute of each of said startingtimes.

5. In a telephone system, a plurality of settable means for denoting theelapsed minutes of duration of a plurality of simultaneously occurringtelephone conversations and a calculating equipment common theretocomprising settable means for denoting the hour and minutes digits ofthe terminating time of said conversations, means for simultaneouslysubtracting each of said elapsed minutes settings from the terminatingtime setting for determining the hour and minuteof the starting time ofeach of said conversations, and means for transmitting code impulsesindicative of the digits of the hours and minutes of said startingtimes.

6. In a telephone system, a plurality of settable means for denoting theelapsed minutes of duration of a plurality of simultaneously occurringtelephone conversations and a calculating equipment common theretocomprising settable means for denoting the hour and minutes digits ofthe terminating time of said conversations, means for simultaneouslydetermining from said elapsed minutes setting if said conversationstarted in the same hour or in the hour preceding the terminating time,means for simultaneously subtracting the elapsed minutes settings fromthe terminating minutes setting for determining the minutes digit of thestarting time of a each of said conversations, and means fortransmitting code impulses indicative of the digits of the hours andminutes of said starting times.

7. In a telephone system, a plurality of conversational circuits eachhaving a device settable in accordance with the minutes of the durationof the conversation thereover and a calculating equipment common to saidcircuits comprising means settable in accordance with the hour andminute digits of the terminating time of conversations over saidcircuits, means for simultaneously determining from the setting of saidduration conversation devices and from the setting of said terminatingtime devices the starting times of all of said conversations, means fortransmitting series of code impulses indicative of the digits of thehour and minute of any staring time, diflerent combinations of whichimpulses are characteristic of every possible value of each digit, andwhereby said impulses are selectively transmitted in difierent codeimpulse combinations characteristic of clifierent values of a digittrolled by said calculating equipment for producing signal impulsesindicative of the digits of the hour and minute of any starting time,diflerent combinations of which impulses are characteristic of everypossible value of each digit, and means for selectively transmittingsaid signal impulses to said conversational circuit.

9. In a telephone system, a plurality of conversational circuits eachhavinga device settable in accordance with the minutes of the durationof a conversation thereover, means settable in accordance with the hourand minute digits of the terminating time of conversations over saidcircuits, means for simultaneously determining from the setting of saidduration devices if said conversations started in the same hour or inthe hour preceding'the terminating time, means for producing series ofcode impulses in accordance with the digits of the hour and minute ofany starting time, different combinations of which impulses arecharacteristic of every possible value of each digit, and means forcontrolling said impulse producing means for producing impulsesindicative of the digits of the preceding hour when said preceding houris the starting time of conversation.

10. In a telephone system, a plurality of conversational circuits eachhaving a device settable in accordance with the minutes of the durationof the conversation thereover, and a calculating equipment common tosaid circuits comprising means settable in accordance with the hour andminutes digits of the terminating time of conversations over saidcircuits, means for simultaneously determining from the setting of saidduration minutes means if said conversations started in the same hour orin the hour preceding the terminating time, means for producing seriesof code impulses indicative of the digits of the hour of any startingtime, difierent combinations of which impulses are characteristic ofevery possible value of each digit, means for controlling'said impulseproducing means for producing codes of impulses indicative of the tensand units digits of the hour of the originating time in the precedinghour, and means for selectively transmitting said code signals to saidconversational circuits.

11. In a telephone system, a plurality of conversational circuits eachhaving a device settable in accordance with the minutes of the durationof a conversation thereover and a calculating equipment common to saidcircuits comprising means settable in accordance with the hour andminutes digits of the terminating time of conversations over saidcircuits, means for simultaneously subtracting duration minutes settingsfrom the terminating minutes setting for determining the minutes digitsof the starting time of each conversation, means for producing codes ofimpulses indicative of the tens and units digits of the minutes of anystarting time, different combinations of which impulses arecharacteristic of every possible value of each digit, and means forselectively transmitting signals in accordance with the tens and unitsdigits of the minutes of the starting hour of conversation over saidconversational circuits.

12. In a telephone system, a plurality of conversational circuits eachhaving a device settable in accordance with the minutes of the durationof a conversation thereover, and a calculating equipment common to saidcircuits comprising an hour switch settable in accordance with the hour,a plurality of multi-wiper switches settable in accordance with the tensdigit of the minutes and a plurality of multiwiper switches settable inaccordance with the units digit 0! the minutes of the terminating timeof conversation over said circuits, said latter switches having bankterminals in a plurality of their bank levels each allocated to adiiferent possible settable position of said duration devices, asequence switch, means under the joint control of said sequence switchand said hour switch for transmitting codes of impulses indicative ofthe digits of the hour of the terminating time and under the control ofsaid sequence switch alone for transmitting codes of impulses indicativeof the minutes of said hour, different combinations of which impulsesare characteristic of every possible value of each digit, and aplurality of relays operable in difierent combinations under the jointcontrol of said tens digit minute switches and said sequence switch andunder the sole control of said sequence switch for selectivelyestablishing parsaid other switches to determine the starting time ofsaid first switch, and means controlled I by said'last-mentioned meansfor transmitting switch.

code signals indicative of the digits of the hour and minute of thestarting time of said first ESMOND P. G. WRIGHT.

